In one proposed call redirection telephone system, calls made to a toll free 800 service number are routed to the subscriber's primary location via a telephone network switch operating in conjunction with a specially configured adjunct processor. The adjunct processor monitors the call and the adjunct is signaled, typically by a dual tone multifrequency signal (DTMS) sequence if the call is to be redirected from the primary location to an alternate location. The adjunct processor places the calling party on hold and initiates a call to the alternate location on an outgoing trunk to the network switch in such a way that it emulates the routing call treatment and billing characteristics of a call as if it were made from the original calling party location to the alternate location. The subscriber of the originally dialed toll-free 800 number pays only for the portion of the call in which the primary location is active. The subscriber providing the 800 toll free number for the alternate location pays for the portion of the call in which the alternate location is involved as though the call originated from the customers location and proceeded directly to the alternate location without having been rerouted at the network switch. Thus, at the primary location, the subscriber is not charged for any period of time which is not used at the primary location by the subscriber.
Redirection is completed in one of three ways: 1) blind transfer, 2) consultation, or 3) conference. With blind transfer, the primary location disconnects before or while the second call is being established. When the second call has been established, the adjunct processor bridges the original call with the call to the alternate location, thereby completing a path from the customer location to the alternate location which bypasses the primary location.
With consultation, a voice path is established between the primary location and the alternate location, while the calling party remains on hold. The attendant at the primary location can then disconnect at which time the calling party is removed from hold and enabled to converse with the person now at the alternate location. Alternately, the person now at the alternate location can disconnect, enabling the primary location to initiate another call redirection. If the calling party disconnects, the entire call is terminated.
If a conference call is desired, the primary location can request interconnection or bridging of the calling party with both the primary and alternate locations for a three way conference call.
Although the described system provides for call redirection so that a subscriber is not charged for any period of time which is not "used" by that subscriber, the system still preferably uses a human operator at the primary location for signalling the adjunct processor when a redirect signal is required. Additionally, announcements made from the adjunct processor to the primary location are voice announcements. In some industries, the subscribers prefer voice response units. Voice response units are common with subscribers such as airline services and other similar services which require a bank of announcements for interaction with the calling party.
It is also desirable to segment various call redirection capabilities for use with either a human agent or voice response unit on the subscriber premises. For example, some redirecting parties may retry redirection if a dial tone is obtained during redirection, but at the same time, allow quick disconnect of the redirecting party if the connection is made such as in blind transfer. The above system does not provide such segmentation.
Additionally, the above system has high operating cost associated with operating the adjunct processor in monitor mode when a "hairpin" connection is made through the adjunct processor. In this connection the calling party is connected to the primary location through the adjunct processor back to the 4ESS switch and over a second voice path to its destination at the alternate location. The adjunct processor remains in this "monitor mode" in a "hairpinned" state for the duration of the call and ties up adjunct and 4ESS resources.
It is therefore desirable to maintain the call between the calling party and alternate location without using the adjunct processor throughout the duration of the call.